'09 FZ6R Jerky When Cruising On Flat Road


flyingdutchman

New Member
Hey guys and gals! I'm new on here and a new FZ6R owner. I've noticed some jerkiness while riding when I'm maintaining a constant speed on a flat road. It runs perfectly smoothly otherwise. Not sure if it's the chain?

Any help would be appreciated :)
 

Jerzee55

Member
Notice any change in RPM? Any noise from chain. If you are worried about the chain, inspect it for tight spots, make sure it is clean, lubricated, and has the proper slack...0 and your sprockets are also shaped properly. Doubt the chain is the issue though... More info on bike, mileage, overall condition would be worth posting for some better input... :)
 

flyingdutchman

New Member
Thanks for the reply Jerzee55. I kept a close eye on it on my ride today. It only seems to happen when the engine gets very hot, like it does when you're in heavy traffic and not moving much or very quickly. The tach needle jerks up and down with the jerking of the bike, so that's as close to noticing any change in RPM as I get. There is a noise that I always hear on the bike which I'm still investigating. I initially thought it was brake rub, but applying either brake makes no difference and it also only happens when the engine is under load. Also wondering about chain.sprockets for this one. Hard to explain what the noise sounds like with words :) I would describe it as a wishwishwishwishwish sound. No idea if that even remotely helps you.

As for more details on the bike. As I mentioned before, '09 FZ6R, 28,000km on the clock, seems to be in excellent condition overall. I've only had it since early April and I'm the 4th owner. Bike is bone stock other than a K&N air filter. Let me know if you have any other questions :)
 

Jerzee55

Member
It you think it may be temp related, check your running temp. See if you can notice any correlation. Assuming all 'scheduled' maintenance has been done, not sure where to even begin. :) Talk with previous owner and see if he noticed any heat related issues. Maybe someone else could jump in here? ;)
 

flyingdutchman

New Member
It happens when the running temp is between around 95-105 (I think). No idea about maintenance history - one of the previous clowns (I mean owners) lost it. Previous owner seemed a bit clueless. Only clues that anything had been done is that the chain looked reasonably clean and the engine oil and brake fluid are both in good shape. I forgot to mention that I've been running 94 octane Chevron and I've run 2 bottles of Lucas Oil Deep Clean through it.
 

flyingdutchman

New Member
So ended up getting a PC5 and going to a tuner (not in an attempt to fix this). I can't remember exactly his explanation, but he said that what I was experiencing is characteristic of Yamaha because of the way the bike is fuelled. Put the bike on the dyno and for the first time saw how the chain was bouncing around like mad (so much so that it was creating waves on the dyno reading). Pulled it off, swapped the chain. Wish-wish-wish noise is gone now (so suspicion around that confirmed). Did the tune and now the bike runs as smooth as a hot knife through butter. No more jerking, no more wish-wish, throttle response is MUCH sharper (he said my TPS reading was WAY off), engine runs cooler (because it's not so lean anymore) - all in all a much better ride. Haven't had the time to do much riding since then (my daughter is 1 month old), but looking forward to doing some more rides with it now. Thanks for all the input here guys - appreciate it!
 

Boost

New Member
So sounds like Jerzee55 was right, tight spots in the chain would most likely happen to do this, especially as the chain would differ in tightness, so every time the chain went through the sprocket it would hit one tight spot right before the normal tension, this would fluctuate revs when your riding. But it doesn't make sense as to why you seemed it only happened when the bike got hot... interesting.
 


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